fame_register man page

fame_register() is used to register an object to the library and associate a type with it. Upon initialisation with fame_init , libfame looks for the fame_profile_t object associated with the "profile" type and calls its 'init' function. Then this object may get other objects through fame_get_object , and so on. Thus, fame_register enables the use of objects from the application inside the library, and can be used to change or extend the default behaviour of the library.

context is the context handle previously returned by fame_open

type is a type identifier to be associated with the object for further retrieval through fame_get_object.

will try to get the object associated with "profile/mpeg4/simple" and register it for the "profile" type as well. This piece of code, called just after fame_open and just before fame_init would effectively have libfame produce MPEG-4 output instead of default MPEG-1.